Waterhemp Meets Its Match

Midwest growers struggling with waterhemp issues have a new information resource.

Biology and Management of Waterhemp has been created to help growers minimize yield losses from waterhemp and manage the development of herbicide resistance. The brochure is the result of a collaboration of university weed scientists Kevin Bradley with University of Missouri, Bob Hartzler with Iowa State University, and Dawn Nordby with University of Illinois.

"Waterhemp is probably the number one concern in the Midwest because everyone has it," Nordby says. Besides a historical background, the brochure addresses waterhemp density and its potential impacts on yield present the biggest concern for growers.

"The other issue is that waterhemp control does significantly increase management costs in terms of additional traditional applications," Hartzler says. "The adaptability of waterhemp to our management practices is the primary reason it has become the number one weed problem for many farmers in the Western Corn Belt."

One of the primary goals of the publication is to address the current waterhemp situation and to encourage growers to take action now.

"We wanted to paint a pretty clear picture of what will happen when we develop resistance to glyphosate. We will basically lose all our mode of actions for controlling waterhemp," Nordby says. "But, there are options out there to prevent this and if farmers want to do something about this problem, they need to do it now."

"The number one treatment method is to avoid applying the same herbicide year after year — that is where prevention meets management," Bradley says. "The key is mode of action rotation. By using an effective preemergence herbicide like Sonic, Authority First, Valor, Dual II Magnum, or any of the other options listed in this publication, you can control populations that have exhibited resistance."

Biology and Management of Waterhemp is one of 10 publications in The Glyphosate, Weeds and Crops Series. The goal of the series is to create an easy-to-use tool for retailers, crop advisors, and growers that will help them manage weeds and preserve the benefits of the Roundup Ready cropping system technology.

A copy of the publication is available through the Glyphosate Stewardship Working Group’s Web site at www.glyphosateweedscrops.org or by contacting their state Extension weed scientist.